The field of the invention is that of methods for assisting with the implantation, along a railway track, of access points of a radio-communications infrastructure.
A communication system, for example of the DCS “Data Communication System” type, is a component of the architecture for controlling train traffic, for example of the CBTC “Communication Based Train Control” type.
The communication system is based on a radio-communications infrastructure including a plurality of access points, fixed to the ground, which are distributed along the track. An access point allows establishment of a wireless connection with a device on board a train running along the track, when this device is located inside the coverage cell associated with the access point. The wireless connection for example observes the WiFi 802.11 protocol.
The radio-communications infrastructure should have continuous coverage over the whole of the length of the track, so as to allow a train running along the latter to permanently communicate with the ground, in order to exchange data relating to the control and to the safety of its movement.
Accordingly, the implantation of the different access points making up the radio-communications infrastructure should lead to obtaining continuous coverage, i.e. such that the coverage cells of two access points successively positioned along the track partially overlap.
Up to now, the implantation of access points is achieved on site according to a plan resulting from a theoretical study conducted in the engineering office. This study takes into account significant margins for guaranteeing the continuity of the coverage of the infrastructure to be achieved.
The implantation includes temporarily setting up access points at kilometric points indicated on the plan.
Next, a coverage study is carried out, consisting of having a vehicle run along the track between the pre-positioned access points, so as to check that there is actually continuity in the radio-communications coverage.
Subsequently to this study, the plan is updated. In particular, in the case of discontinuity of the coverage, an additional access point is positioned so that its coverage cell will fill the identified space, or both neighboring access points are brought closer to each other in order to fill the identified space.
Finally, the access points are definitively set up at the kilometric points indicated on the updated plan.
This way of proceeding leads to a significant overlap of the different cells between them and therefore to the use of a large number of access points.
Therefore there exists a need for optimizing the number and the placement of the access points of a radio-communications infrastructure along a railway line, while guaranteeing that a radio-communications infrastructure is produced forming a continuous coverage.